This invention relates to cartridge based data storage systems. More particularly, the invention relates to the loading and ejection of a disk cartridge to and from a disk drive.
Cartridge based tape and disk data storage devices for storing digital electronic information have been in use in the computer industry for several decades. Removable disk cartridges typically comprise an outer casing or shell that houses a disk-shaped magnetic, magneto-optical or optical storage medium upon which information can be stored. The cartridge shell often comprises upper and lower halves that are formed of injection molded plastic and are joined together to house the disk. Magnetic disk media can be either rigid or flexible and are mounted on a hub that rotates freely within the cartridge. When the cartridge is inserted into a disk drive, a spindle motor in the drive engages the disk hub in order to rotate the disk within the cartridge at a given speed. The outer shell of the cartridge typically has a media access opening proximate one edge to provide the recording heads of the drive with access to the disk. A shutter or door mechanism is provided to cover the head access opening when the cartridge is not in use to prevent dust or other contaminants from entering the cartridge and settling on the recording surface of the disk. The shutter is commonly biased to a closed position with a spring bias. To open the shutter and gain access to the media, the drive employs a mechanism that overcomes the bias of the spring.
Disk drives for use with such removable disk cartridges typically employ either a linear actuator mechanism or a radial arm actuator mechanism for positioning the read/write head(s) of the disk drive on the recording surface(s) of the storage medium, or disk. Because the disk cartridges are designed to be removable from the drive, the linear or radial arm actuators must be able to move off, and away from, the storage medium to a retracted position in order to prevent damage to the head(s) when a cartridge is inserted and removed from the disk drive. Moreover, many removable cartridge disk drives employ a pair of opposing read/write heads for recording and reproducing information on both sides of a storage medium. Typically, the opposing heads are disposed on flexible suspension arms at the distal end of an actuator that allow the heads to fly closely over the respective surfaces of the rotating disk.
Disk drives also require a mechanism for allowing the heads to load only after a cartridge is inserted into the drive. The actuator that carries the recording heads of the disk drive across the recording surfaces of the disk should not be allowed to move unless a disk cartridge is present. In the prior art, mechanical or electrical switches are typically employed to determine the presence of a disk cartridge within the drive. Such switches are typically positioned so that when a disk cartridge is inserted fully into the drive, the cartridge contacts the switch, thereby providing an indication that the disk cartridge is present.
When a user has completed the use of a disk cartridge, a mechanism must be provided to eject the disk cartridge from the drive and substantially simultaneously ensure that the read/write heads are retracted from the disk into a predetermined safe position so as to prevent any damage to the read/write heads. Typically, a tray or spring loaded lever is used to push the cartridge out of the drive. The spring loaded tray or lever is often coupled to the head protection mechanism so that the head protection occurs in unison with cartridge ejection. Ejection of the cartridge from the drive is most often effected by pressing a button located on the exterior of the drive. Depressing such a button signals the drive to retract the read/write heads from the media and eject the media cartridge.
There is trend in the art to reduce the size of storage media drives and cartridges. The mechanisms for ejecting a media cartridge and the linkage to the head retraction require additional disk drive space which runs counter to the movement to reduce the overall size of the drive. Furthermore, the surface area on the exterior of a storage media drive is limited, with little room available for eject buttons to effect the removal of a cartridge from the media drive.
Therefore, there is a need for an intuitive method and apparatus for ejecting a cartridge from a drive that protects against reading and writing errors which may occur when the cartridge is moved while the drive is reading or writing.